This invention relates to a multiple-stage type electrical switchboard, and more particularly to an improved lifting apparatus which lifts up electrical devices such as circuit breakers and draws them into the multiple-stage electrical switchboard and draws them out.
Generally, as shown in FIGS. 1 and 2, a multiple-stage electrical switchboard 10 which contains a plurality of compartments for electrical devices, a lifting apparatus frame 12 which consists of a bucket 14 mounting electrical devices 16, driving gear 18 and trucks 20 is used to facilitate racking movement of electrical devices 16 between positions of electrical engagement and disengagement.
But in this case, not only does the weight and bulk of the lifting apparatus frame 12 become difficult for an electrician to handle, but such is expensive because the lifting apparatus frame 12 contains guide rails 22 which are also used for supporting the bucket 14. It is also necessary to provide the lifting apparatus frame 12 with an area for moving, that is, a passage space for inspection corresponding to the width A and the relatively large accommodating space corresponding to the area BXC as shown in FIG. 2 in front of the electrical switchboard 10.
Furthermore, such lifting apparatus frame 12 is in danger of being turned upside down during jolting on the rough floor such as when an electrician may carelessly move the lifting apparatus frame 12 with the bucket 14 mounting electrical devices on the top of the lifting apparatus frame 12.